Hardeners for incorporated coupler emulsions



b Unlted States Patent Ofitice 25, 1,67

3,316,095 HARDENERS FOR INCORPORATED COUPLER EMULSIONS John H. Van Campen and James L. Graham, Rochester,

N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Oct. 13, 1965, Ser. No. 495,723 9 Claims. (Cl. 96-100) This invention relates to photographic products useful for color prints in which staining is inhibited comprising gelatin-silver halide photographic emulsions, pyrazolone coupler and an isoxazolium salt as a hardener for the gelatin.

In the making of photographic color prints using gelatin layers containing silver halide and couplers which form a magenta image, staining has often occurred. Many of the commonly used gelatin hardeners do not prevent this staining or even promote the staining of paper or other supports upon which these layers are applied. As a con sequence, the quality of the prints obtained may be adversely affected.

One object of our invention is to provide photographic products adapted to the making of color prints in which staining effects are inhibited and the sensitometric properties are not adversely affected. Another object of our invention is to provide photographic products containing gelatin-silver halide photographic emulsions, pyrazolone couplers and as the hardener for the gelatin an isoxazolium salt.

We have found that photographic products featuring the combination of emulsions having silver halide as the photosensitive element, a pyrazolone coupler which is capable of forming an azomethine dye with a phenylenediamine developer and a hardener having the following general formula:

n 1 iR L I in which R is an aliphatic hydrocarbon group of 1 to 4 carbon atoms either with or without a sulfonate anion thereon, R and R are each one of the following: hydrogen, unsubstituted alkyl, unsubstituted aryl, alkyl or aryl substituted with halogen, hydroxyl or sulfonate anion, a simple heterocyclic ring such as furyl or R and R together form an alicyclic ring and X is an anion which contributes to the water solubility of the compound such as perchlorate, paratoluene-sulfonate or the like, unless sulfonate anion is already present, attached to R, R or R", will be free of staining when that combination is present on a paper support in its use for making photographic prints. Our invention is useful in combination with pyrazolone couplers such as those described in U.S. iPatent 2,640,766 of Spence and Carroll or US. Patent 2,600,788 of Loria et al.

The compounds which may be employed as hardeners in color emulsions in accordance with our invention are isoxazolium hardeners as are described in more detail in Burness and Wilson application Ser. No. 248,201, filed Dec. 31, 1962, now abandoned. We have found that combinations containing pyrazolone coupler, silver halide emulsion and hardener, the latter being of the type described in Ser. No. 248,201, have good brightness characteristics and exhibit less stain than compositions of like nature formerly used. Photographic layers in accordance with our invention show reduced stain and no adverse sensitometric eifect when an isoxazolium salt is used in a proportion which produces satisfactory hardness in layers containing gelatin-silver halide and an isoxazolium material. No effect upon dye hue or stability of the photographic product has been observed either as a result of the various components used or of the retention of proc essing chemicals. Our invention avoids stain generally and if any staining should occur it would only be a neutral stain of the lowest possible density.

In the emulsions in accordance with our invention gelatin is primarily employed as the vehicle for the silver halide. However, if desired, the presence of polymers auxiliary to the gelatin may be present such as ethyl acrylate-acrylic acid copolymer, butyl acrylate-acrylic acid copolymer or some other acid substituted polymeric vehicle. Not only does our invention relate to color emulsions in which pyrazolone coupler is present but also included are color emulsions in which the coupler is provided from solution in some water immiscible solvent so as to constitute a packet form of emulsion. Our invention includes any of the recognized color photographic emulsions having silver halide as the photosensitive element, pyrazolone coupler and a hardener as described and claimed in Ser. No. 248,201. Our invention includes combinations of silver halide emulsion, hardener of the type described and claimed in Ser. No. 248,201 and pyrazolone coupler 1) when all three of these compo nents are in a single emulsion or (2) when one or more of these components are in a layer other than that containing one or more of these components as for example a multi-layer system in which one of the components is in a layer with or without one or both of the other members of the combination.

The following examples illustrate the advantage of our invention in the obtaining of photographic prints from material using compositions in accordance with our invention:

Example 1 This example illustrates photographic color print material using a hardener of the invention plus a pyrazolone coupler in one case and a conventional type aldehyde hardener plus a pyrazolone coupler in the other in a multilayer photographic color product. In the case of samples B and C one emulsion contains both pyrazolone coupler and a hardener in accordance with the invention. That hardener is also used in the other five layers of the structure but pyrazolone coupler is absent. In the case of sample A the hardener used was an aidehyde-type hardener.

A series of coatings were laid down upon a paper support as follows:

Layer 6-ge1atin layer.

Layer S-red-sensitive silver chlorobromide gelatin consisting of 90 mole percent bromide-Pa phenolic cyan coupler of the type described in US. Patent 2,423,730.

Layer 4gelatin layer+an ultraviolet absorber.

Layer 3-green-sensitive silver chlorobromide gelatin emulsion consisting of mole percent chloride-Fa pyrazolone magenta coupler of the type described in US. Patent 2,600,788.

Layer 2-gelatin layer.

Layer 1blue-sensitive silver chlorobromide gelatin emulsion consisting of 98 mole percent bromide+an acyl acetanilide yellow coupler of the type described in US. Patent 2,875,057 Samples A, B, and C were prepared. A was composed of the layers as outlined. In all of the: layers of Sample A 0.54% of mucochloric acid (based on the weight of the gelatin) was used as the hardener. In Sample B each of the six layers contained 2% (by weight of the gelatin) of 2,5-dimethylisoXazolium-perchlorate. Each of the six layers of Sample C contained 3% (by weight of the gelatin) of 2,5-dimethylisoxazolium-perchlorate. The various photographic color print Samples A, B and C were exposed and processed in a phenylenediarnine type developer and the percent refluctance of each was determined by means of a recording spectrophotometer at 440 m and the results obtained were as follows:

Higher percent refiuctance shows that the coatings have less stain than the mucochloric acid hardened coatings. Sensitometric tests were run on both fresh and incubated coatings. It was found that the coatings containing the isoxazolium salt were comparable in sensitometric properties to coatings containing mucochloric acid as the hardener. The coatings were also tested for hardness by immersing a strip of each into a p-phenylene diamine type developing solution at pH 10, raising the temperature and observing the point at which the emulsion melted. The isoxazolium salt hardened layers melted at a substantially higher temperature than that when aldehyde type hardener was used. In a second type of hardener test the coatings were subjected to brushing while the coatings were immersed in water and the temperature gradually raised. It was found that the coatings containing the isoxazolium salt hardener were able to withstand a substantially higher temperature than the coatings containing the mucochloric acid hardener.

Example 2 A magenta image-forming layer of the type of incorporated coupler photographic coating described in the example of Table I of US. Patent 3,046,129 of J. L. Graham et al. was prepared by coating a high speed silver bromoiodide emulsion sensitized to the green region of the spectrum, sulfur and gold sensitized and supplied with a dispersion in tri-o-cresylphosphate of a pyrazolone coupler such as coupler No. 7 of US. Patent 2,801,171 of Fierke et al. An isoxazolium salt was used as the hardener, the type and concentrations being listed in the following table together with a control using mucochloric acid. The results obtained were as follows:

Sensitometric tests on fresh and incubated coatings showed that coatings containing isoxazolium salts as hardeners were equal or even better than mucochloric acid hardened coatings. Also stain and overall yellowing was eliminated in those coatings where isoxazolium salts were used as hardeners. Other isoxazolium salts than those in the examples as for instance Z-ethyl-S-phenylisoxazolium-3'-sulfonate and 2 .methyl-S-p-tolylisoxw zolium-3'-sulfonate employed as hardeners in products as described in the examples exhibit results similar to :those obtained in the use of the isoxazolium salt employed in the examples.

The invention has been described in considerable deztail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove, and as defined in the appended claims.

We claim:

1. A photographic element which comprises a support having thereon a plurality of layers in which at least one of said layers contains gelatin-silver halide photographic emulsion, at least one of said layers contains pyrazolone coupler and at least one of said layers contains a hardener having the formula in which R is an aliphatic hydrocarbon grou of 1-4 carbon atoms either with or without a sulfonate anion thereon, R and R are each one of the following: hydrogen, unsubstituted alkyl, unsubstituted aryl, alkyl or aryl substituted with halogen, hydroxyl or sulfonate anion, a simple heterocyclic ring such as furyl or R and R" together form an alicyclic ring and X is ananion which contributes to the water solubility of the compound such as perchlorate, paratoluene-sulfonate or the like, unless sulfonate anion is already present, attached to R, R or R. 2. A multilayer photographic product in which at least one layer contains gelatin-sliver halide photographic emulsion, at least one layer contains pyrazolone coupler and at least one layer contains a hardener having the formula:

in which R is an aliphatichydrocarbon group of l4 carbon atoms either with or without a sulfonate anion thereon, R and R are each one of the following: hydrogen, unsubstituted alkyl, unsubstituted aryl, alkyl or aryl substituted with halogen, hydroxyl or sulfonate anion, a simple heterocyclic ring such as furyl or R and R"'together form an alicyclic ring and X is an anion which contributes to the water solubility of the compound such as perchlorate, paratoluenesulfonate or the like, unless sulfonate anion is already present, attached to R, R or R".

3. A multilayer photographic product in which at least one layer contains gelatin-silver halide photographic emulsion, at least one layer contains pyrazolone coupler and at least one layer contains dimethylisoxazoliurnperchlorate.

4. A multilayer photographic product in which at least one layer contains gelatin-silver halide photographic emulsion, at least one layer contains pyrazolone coupler and at least one layer contains Z-ethyLS-phenylisoxazolium-3-sulfonate.

5. A multilayer photographic product in which at least one layer contains gelatin-silver halide photographic emulsion, at least one layer contains pyrazolone coupler and at least one layer contains Z-rnethyl-S-p-tolylisoxazolium-3'-sulfonate.

6. A gelatin-silver halide photographic emulsion Which contains pyrazolone coupler and dimethylisoxazoliumperchlorate.

7. A gelatin-silver halide photographic emulsion useful in color photography which contains a pyrazolone coupler capable of forming an azomet-hine dye with a phenylenediamine developer and a hardener having the formula:

'T 1 ia l u in which R is an aliphatic hydrocarbon group of 1-4 carbon atoms either with or without a sulfonate anion thereon, R and R" are each one of the following: hydrogen, unsubstituted alkyl, unsubstituted aryl, alkyl or aryl substituted with halogen, hy-droxyl or sulfonate anion, a simple heretocyclic ring such as furyl or R and R" together form an alicyclic ring and X is an anion which contributes to the water solubility of the compound such as perchlorate, paratoluenesulfonate or the like, unless 5 sulfonate anion is already present, attached to R, R or R".

8. A photographic element comprising a support bearing a plurality of layers which collectively contain silver halide, pyrazolone coupler and 2,5-dimethylisoxazoliumperchlorate.

9. A photographic element comprising a support bearing a plurality of layers, one of which layers contains silver halide, pyrazolone coupler and a hardener having the formula:

in which R is an aliphatic hydrocarbon group of 1-4 carbon atoms either With or Without a sulfonate anion thereon, R and R" are each one of the following: hydrogen,

unsubstituted alkyl, unsubstituted aryl, alkyl or aryl substituted with halogen, hydroXyl or sulfonate anion, a simple heterocyclic ring such as furyl or R and R together form an alicyclic ring and X is an anion which contributes to the Water solubility of the compound such as perchlorate, paratoluenesulfonate or the like, unless, sulfonate anion is already present, attached to R, R or R".

References Cited by the Examiner UNITED STATES PATENTS 3,060,028 10/1962 Dersch 96109 X NORMAN G. TORCHIN, Primary Examiner. I. RAUBITSCHEK, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,316 ,095 April 25 1967 John H. Van Campen et a1.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 55, "2,640,766" should read 2,640,776

Column 3, line 55, after "equal insert to Signed and sealed this 3rd day of February 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr.

Attesting Officer Commissioner of Patents WILLIAM E. SCHUYLER, JR. 

1. A PHOTOGRAPHIC ELEMENT WHIHCH COMPRISES A SUPPORT HAVING THEREON A PLURALITY OF LAYERS IN WHICH AT LEAST ONE OF SAID LAYERS CONTAINS GELATIN-SILVER AHLIDE PHOTOGRAPHIC EMULSION, AT LEAST ONE OF SAID LAYERS CONTAINS PYRAZOLONE COUPLER AND AT LEAST ONE OF SAID LAYERS CONTAINS A HARDENEER HAVING THE FORMULA 